Open chain nitrogen compounds. Part X. Thermolysis of α-diazoacetanilides in methanol: a convenient synthesis of α-methoxyacetanilides from ethyl N-(arylazo)glycinate

1986 ◽  
Vol 64 (4) ◽  
pp. 799-802
Author(s):  
Kumudini U. K. Gamage Nicholas ◽  
Keith Vaughan
Keyword(s):  
Tertiary Amine ◽  
Methanol Solution ◽  
Small Scale ◽  
Nitrogen Compounds ◽  
Rare Type ◽  
Open Chain ◽  
Amide Derivative ◽  
Convenient Synthesis ◽  
Synthetic Equivalent ◽  
Electron Withdrawing Group

α-Diazoacetanilides (4), which are readily available from the open-chain triazenes (2), undergo thermolysis in methanol solution to afford the α-methoxyacetanilides (5), an apparently rare type of ether/amide derivative. The methanolic thermolysis is inhibited by the presence of a tertiary amine in the solvent, suggesting that a carbocation, rather than a carbene, intermediate is involved in the conversion of the diazo-amide to the methyl ether. This hypothesis is supported by the retardation of the reaction in the presence of an electron-withdrawing group in the para position of the anilide. The conversion 4 → 5 was also observed, on a small scale, under photolytic conditions. It is suggested that the α-diazoacetanilide represents a useful synthetic equivalent for the synthon ArNHCOCH2+.

Open-chain nitrogen compounds. Part II. Preparation, characterization, and degradation of 1(3)-Aryl-3(1)-methyltriazenes; the effect of substituents on the reaction of diazonium salts with methylamine

1977 ◽  
Vol 55 (10) ◽  
pp. 1701-1709 ◽  
Author(s):  
T. Patrick Ahern ◽  
Handrick Fong ◽  
Keith Vaughan
Keyword(s):  
Degradation Products ◽  
Diazonium Salt ◽  
Diazonium Salts ◽  
Nitrogen Compounds ◽  
Open Chain ◽  
Effect Of Substituents ◽  
Electron Withdrawing Group

Treatment of the diazonium salts, X•C6H4N2+, with aqueous methylamine affords good yields of the monomethyltriazenes, X•C6H4•N=N•NHMe, when the substituent is a strongly electron-withdrawing group (X = o-, m-, and p-NO2; o-, m-, and p-CO2R; p-CN and p-COCH3). Preparation of the triazene from the p-bromobenzene diazonium salt was accompanied by formation of a pentaazadiene. Monomethyltriazenes were not obtained when diazonium salts containing other substituents (X = H, p-CH3, o-CF3, p-Cl, p-F, p-NMe2, p-OH, p-OCH3, p-Ph, p-NHCOCH3) were treated with methylamine. In these cases the products were either pentaazadiene, or 1,3-diaryltriazenes or unstable materials. The monomethyltriazenes vary considerably in stability and give rise to a number of different degradation products, which were either diaryltriazenes or 3-alkyl-1,3-diaryltriazenes or simply arylamines. 1(3)-(p-Nitrophenyl)-3(1)-methyltriazene was found to be a moderately effective methylating agent.

Convenient Synthesis of Fluorescent Chromeno[4,3-d]pyrimidines from Electron-Deficient 3-Vinylchromones

Synthesis ◽  
2019 ◽  
Vol 52 (01) ◽  
pp. 40-50 ◽  
Author(s):  
Nikita M. Chernov ◽  
Roman V. Shutov ◽  
Anastasia E. Potapova ◽  
Igor P. Yakovlev
Keyword(s):  
Stokes Shift ◽  
Mild Conditions ◽  
Convenient Synthesis ◽  
Acid Fragment ◽  
Wide Range ◽  
Powerful Approach ◽  
Reaction Proceeds ◽  
Electron Withdrawing Group ◽  
Blue Range ◽  
Acetic Acids

We report an easy and powerful approach to the synthesis of novel chromeno[4,3-d]pyrimidine-5-acetic acids through ANRORC reaction of electron-deficient 3-vinylchromones and 1,3-N,N-binucleophiles. The reaction proceeds under mild conditions (EtOH, rt) and is applicable to a wide range of substrates. The described compounds show fluorescence in the violet-blue range (390–460 nm) with Stokes shift of 40–80 nm and moderate quantum yield (0.15–0.20). As the electron-withdrawing group is conserved in the form of an acetic acid fragment, these compounds may readily be functionalized or conjugated to a required substrate for (bio)analytical purposes.

Open-chain nitrogen compounds. Part XV. A kinetic study of the hydrolysis of 1-aryl-3-aryloxymethyl-3-methyltriazenes and related triazenes

1992 ◽  
Vol 70 (8) ◽  
pp. 2224-2233 ◽  
Author(s):  
Keith Vaughan ◽  
Donald L. Hooper ◽  
Marcus P. Merrin
Keyword(s):  
Rate Constant ◽  
Order Rate Constant ◽  
Buffer System ◽  
Open Chain ◽  
Nucleophilic Displacement ◽  
Ether Oxygen ◽  
Rate Of Hydrolysis ◽  
Electron Withdrawing Group ◽  
Ph Range ◽  
Kinetics Of

The kinetics of hydyrolysis of a series of 1-aryl-3-aryloxymethyl-3-methyltriazenes, Ar-N=N-NMe-CH2OAr′, was studied over the pH range 2–7.5. Reactions were followed by the change in UV absorbance spectra of the triazenes. The aryloxymethyltriazenes decompose more slowly at pH 7.5 than the hydroxymethyltriazenes, Ar-N=NMe-CH2OH; the hydrolysis is favoured by the presence of an electron-withdrawing group in Ar′. A mixed isopropanol/buffer system was developed in order to improve solubility of the aryloxymethyl triazenes. Lowering the pH caused an increase in the rate of hydrolysis and under strongly acidic conditions an electron-withdrawing group in Ar′ actually slows down the reaction. A Hammett plot of the pseudo-first-order rate constant, kobs, is curved, indicating that two or more mechanisms operate simultaneously and that the contribution of each mechanism is substituent-dependent. A plot of kobs vs. [buffer] is linear; the slope of the plot affords the rate constant, kb for the buffer-catalyzed reaction for each substituent. A Hammett plot of kb vs. σ is linear with ρ = +0.55, suggesting that the buffer-catalyzed reaction involves nucleophilic displacement of the phenoxy group by the buffer anion. Further analysis afforded the specific acid-catalyzed rate constants, [Formula: see text], for each substituent; this component of the reaction has a negative ρ, consistent with a mechanism involving protonation at the ether oxygen. The postulation that specific acid catalysis is a component of the reaction mechanism was confirmed by the observation of a solvent deuterium isotope effect, 2.28 > kH/kD > 1.60. Only the p-NO2 and p-CN phenyloxymethyltriazenes showed any spontaneous decomposition.

Open chain nitrogen compounds. Part XIII. 1-Aryl-3-arylthiomethyl-3-methyltriazenes and 3-(arylazo)-1,3-thiazolidines

1988 ◽  
Vol 66 (10) ◽  
pp. 2487-2491 ◽  
Author(s):  
Keith Vaughan ◽  
Hartford W. Manning ◽  
Marcus P. Merrin ◽  
Donald L. Hooper
Keyword(s):  
Nuclear Magnetic Resonance ◽  
Magnetic Resonance ◽  
Active Metabolite ◽  
Aqueous Acetone ◽  
Rotational Isomerism ◽  
Nitrogen Compounds ◽  
Open Chain ◽  
New Class ◽  
Nuclear Magnetic Resonance Spectra ◽  
Show Evidence

Reaction of 3-acetoxymethyl-1-aryl-3-methyltriazenes with sodium thiophenolate or thiocresolate in anhydrous dimethylformamide affords a new series of 3-arylthiomethyltriazenes (2), Ar-S-CH2-NMe-N=N-Ar′. These triazenes are remarkably labile in aqueous buffer and may be good pro-drugs for the active metabolite of the antitumour dimethyltriazenes. The reaction of arenediazonium fluoroborates with 1,3-thiazolidine in aqueous acetone affords a new series of N-arylazo-1,3-thiazolidines (4); the arylazothiazolidines represent a new class of triazene in which the N3 nitrogen is incorporated into a heterocyclic unit, in this case a 1,3-thiazolidine. Nuclear magnetic resonance spectra of the arylazothiazolidines show evidence for rotational isomerism of the exocyclic N2—N3 bond in the triazene moiety.

1008. Infrared spectra of open-chain boron–nitrogen compounds

1960 ◽  
Vol 0 (0) ◽  
pp. 5239-5246 ◽  
Author(s):  
D. W. Aubrey ◽  
M. F. Lappert ◽  
H. Pyszora
Keyword(s):  
Infrared Spectra ◽  
Nitrogen Compounds ◽  
Open Chain ◽  
Boron Nitrogen
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